Apparatus for folding leather pieces and the like



Jan. 15, 1963 G. FREEMAN, JR 3,073,141

APPARATUS F'OR FOLDING LEATHER PIECES AND THE LIKE Filed June 23, 1960 3 Sheets-Sheet 1 A n o o 7 f @7 -3 o /0 O 3- o zo /4 /0 H'n O I l 'I l /f h l I Il f 1| :il O "r-v 9\ y *M V Uw-@LMS 0 I ITW' /7 q u 36 p /7 4 V6 36 3.6 V6 ,e Ee.

/0 A m 23 INVENTOR.

Jan. 15, 1963 l., G. FREEMAN, JR 3,073,141

APPARATUS FOR FOLDING LEATHER PIECES AND THE LIKE Filed June 25, 1960 3 Sheets-Sheet 2 FIG. 12.

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1N VEN TOR. au/s [26e/WAN, Je.,

BY /Zj Jan. 15, 1963 L. G. FREEMAN. JR

APPARATUS FOR FOLDING LEATHER PIECES AND THE LIKE Filed June 23, 1960 3 Sheets-Sheet 5 ATTORN EVS.

Unite A States pany of Ohio Filed June 23, 1960, Ser. No. 38,314 15 Claims. (Cl. 69-1) This invention relates to machines primarily intended for use in the shoe industry for forming decorative leather articles, such as bows, discs, simulated buckles and the like. Such ornamental articles are usually formed from a preshaped piece of sheet material-usually leatherthe margins of the piece being doubled back to form a finished edge. A suitable bonding adhesive or cement is normally first applied to the areas to be doubled back or to the areas against which the double back portions are to be juxtaposed, so that the parts will be secured together in the folded condition. In many instances a thin stiifening element, such as stiff paper or similar material, is cemented to the piece before the margins are folded, the marginal areas of the piece extending beyond the edges of the stiffener so that, upon folding, the marginal areas will be folded about the edges of the stiffener and will be cemented to the exposed face thereof.

The instant invention relates to improve apparatus for forming decorative articles of the character described, which articles may be formed vWith or without a stiffener and which, depending upon their shape, may be simultaneously subjected to a plurality of folding operations. Thus, in accordance with the instant invention, articles having cut-outs therein may have both their outer and inner edges folded and secured in a single press opera-tion.

Still a further object of the instant invention is the provision of improved mechanism by means of which the operator may readily position and align the pre-shaped work pieces or blanks for the subsequent folding and pressing operations, wherein means are provided for automatically stripping the folded pieces from the forming dies, and wherein the moving parts of the machine are coordinated so as to function in an operating cycle under the control of the operator.

The foregoing, together with other objects of the instant invention which will appear hereinafter or which will be apparent to the skilled worker in the art upon reading this specification, I accomplish by those constructions and arrangements of parts of which I will now describe certain exemplary embodiments.

Reference is now made to the accompanying drawings wherein:

FIGURE 1 is a side elevational view of a press mechanism which may be employed in accordance with the invention.

FIGURE 2 is a front elevational view of the press mechanism.

FIGURE 3 is an enlarged plan View of a die assembly in accordance with one embodiment of the invention.

FIGURE 4 is a verticalsectional View taken along the line 4-4 of FIGURE 3.

FIGURES 5 through 8 `are vertical sectional views taken along the line 5 5 of FIGURE 3 illustrating succe'ssiv stages in the movement of the dies. y

FIGURE 9 is a plan View of a piece folded by means of the die illustrated in FIGURES 3 through 8.

FIGURE is a perspective View of the upper die ele# ment for folding the decorative piece illustrated in FIG- URE 9. I

FIGURE l1 is a plan View of an elliptical decorative piece having a center cut-out.

FIGURES 12 and 13 are fragmentary vertical sectional atent 3,073,141 Patented Jan. 15, 1963 ice views similar to FIGURE 4, but illustrating the die elej lines -15 of FIGURE 14.

FIGURES 16 through 18 are fragmentary Vertical sectional views illustrating self-stripping die mechanism for folding the decorative piece of FIGURE 14.

Referring first to FIGURES l and 2 of the drawings, I have therein illustrated a conventional bench type cut-out machine of the character usually employed in shoe man-v ufacturing plants to perform a variety of cutting operations andthe like. The mechanism illustrated comprises a table or bench 1 supporting the machine head 2 provided with a vertically reciprocating upper platen 3 coacting with a fixed lower base platen or anvil 4, the reciprocating upper Vplaten being actuated by means of well known actuating mechanism 5 under the control of the operator through the foot treadles 6 and 6a, the treadle 6 having a direct mechanical connection to the upper platen member 3 and serving to lower the upper platen member in a slow gentle stroke, whereas the treadle 6a acts through suitable trip mechanism to effect a power stroke, power being supplied through driven shaft 7 operatively connected to the drive motor 8.

In accordance with one embodiment of the invention, the press is provided with upper and lower die members of the character illustrated in FIGURES 3 through 8 and 10, the latter ligure illustrating an upper die member adapted to be secured to the upper platen member 5. The upper die member comprises a Abase plate 10 mounting a male die 11 configured to conform to the body to the decorative piece being acted upon :and which, in this instance, comprises a bow. The base plate 10 also mounts sets of 'stripping pins 12, 13 which, as will be explained more fully hereinafter, act to remove the folded pieces from a cavity forming a part of the lower die element.

Referring now to FIGURES 3 and 4, the lower die element comprises a base plate 14 adapted to be supported onthe lower platen member 6, the base plate mounting a die block 15 supported by a plurality of vertically movable guide pins 16 surrounded by springs 17 extending between the base plate 14 and the die block 15, the springs normally serving to bias the die block to its uppermost position. Along its opposite side edges the die block 15 is provided with guide channels 13 mounting a horizontally movable sliding plate 19 provided with a forwardly projecting handle 20 by means of which the plate 19 may be moved back and forth relative to the die block 15, the extent of movement of the sliding plate being determined by the elongated slot 21 in the die block which is engaged by the stop pin 22 projecting downwardly from the undersurface of the sliding plate.

As possibly best seen in FIGURES 3 and 6, the sliding plate is provided with a configured orice 23 through which the male die is adapted to pass, the orifice 23 being surrounded by a recessed shoulder 24 which supports the marginal edges of the ornamental piece to be folded. The shoulder 24 thus serves as a means for positioning the ornamental piece in alignment with the die elements. An ornamental piece is illustrated at 25 in FIGURE 9, the marginal edges thereof which are supported by the shoulder 24 being indicated in dotted lines at 26.

The sliding plate 19 has a iirst or loading position in which it projects forwardly from the press in the direction of the'machine operator. This position is illustrated in FIGURES 648; and it lwill be understood that when the plate is in the forward or loading position, the operator will place a blank in the recess defined` by the shoulder 24,

whereupon the sliding plate 1L will be shoved rearwardly to its operating position in which the blank is in vertical alignment with the male die element 11.

' A female die cavity 27 is formed in the die block 15 in vertical alignment with the male die element 11, the cavity 27,` extendingthrough the die block and normally closed bya pressure block 28l mounted on a pressure plate 29 overlying base platey 14, the pressure block being lbiasedupwardly, by meansof springs 30 (FIGURE 4). The pressure block 28 thus normally fills the female die cavity 27 but is moved ldownwardly-by the male die 11 as it enters the female die cavity.

When the operator actuates the treadle 6 to slowly reciprocate the upper die VVassernbly,ther male `die element 11 willY move downwardlythrough the orifice 23, carrying the blank 25 with it, the marginal edges 26 of the blank being turned upwardly about the sides of the male die. element, the parts thus assuming the position illustrated in FIGURE wherein `it will be` seenV that the.

marginal edges 26 of the blank are maintained in an upwardly turned position by the walls of the female die cavity 27. At the same time the downward movement of the male die element 11 moves the pressure block 28 and plate 29 downwardly, the plate 29,"when the upper die kelement reaches its lowermost position, being juxtaposed to the upper surface of the base plate 14. As the plate.

29 moves downwardly it contacts the spring biased locking elements 31 which are cammed outwardly by the plate but-which, when the plate seats against the base Plate 14, spring inwardly to secure the pressure plate 29 and block 28 in the lowermost position so that, as the male die element 11 travels upwardly on its return stroke, the blank,

25 will remain in the female die cavity seated against the upper surface'of the block 2S.

As will be evident from an inspectionlof FIGURE 5, the'wall surfaces of the orifice 23 in the sliding plate 19 are offset inwardly with respect. to `the'wall surfaces of the female die cavity 27. This offset provides an abutment Veffective to prevent the blank 2S from being pulled upwardly by the male die element 11 should the blank tend to stick thereto, the free edges of theV upwardly turned marginal portions 26 engaging beneath the abutment provided by the inwardly offset walls of the orifice.

When the male die element 11 has returned to its uppermost position, the operator again grips the handle 21 and slides the plate forwardly to the loading position so that another blank maybe positioned in the recess defined by the shoulder 24. However, as will be seen in FIGURE 6, when the sliding plate 19 is moved to its forward position, a configured cavity 32 formed in the undersurface of the plate 19 will be brought into vertical' alignment with the female die cavity 27. As will be apparent from FIG- URE 3, the cavity 32 is configured to conform to the Vbody of the ornamental piece being folded; and again thereby causing the blank 25 to be pushed upwardly into the cavity r32', the rounded corners of the cavity causing.

the upwardly projecting marginal areas 26 ofthe blank to lbe folded inwardly to the position illustrated in FIGURE 7. It willvbe understood that adhesive will have been applied to the upper surfaceof the marginal areas 26 prior to the positioning of the blank on the pressure plate. In order to avoid` adherence` ofthe adhesive to the parts of the die elements, a so-called cohesivesubstance may be employed which-has theproperty of adhering only to itself. Thus, by preapplying such cohesive to the marginal edges` of the blank and `Yto the portions of the blank to which such marginal portions are juxtaposed when infolded, the parts may be readily adhered together without fouling the die elements.

As already indicated, the second downward stroke of the upper platen will be a power stroke effective to drive the body block 15 to its lowermost position and immediately release the block for` upward movement under the influence of thespring 17. As the die block moves downwardly, it exerts a camntling action against the spring pressed locking elements 31, as seen in FIGURE 7, thereby releasing the plate 29 for upward movement, the parts returning to the position illustrated inFIGURE 8. In this position the now folded piece 25 is` containedy wholly within the cavity 32, the uppermost surface of the pressure block 28 lying essentially coplanar with the upper surface of die block 15. Then, when the sliding plate 19 is moved rearwardly to its operating positioncarrying with it the next successive blank to be folded, the already folded blank contained in the cavity 32 will be carried rearwardly and will be retained in the cavity until the next down stroke of the male die element, at which time the sets of stripper pins 12, 13 will pass through corresponding sets f of openings 12a, 13a in the plate 19 overlying the cavity 32. Thus, as seen in FIGURE 5, the stripper pins act to push the folded piece from the cavity 32 Where it may be collected and removed from the machine. arrangement, two ornamental pieces are acted upon simultaneously, one being stripped from the cavity 32 while the next successive blank is engaged by the male die element and forced downwardly into the female die cavity.

FIGURES 1l, 12 land 13 illustrate a modification of the device particularly su-ited to the formation of ldecor-ative pieces having a center cut-out, such as the piece 35 seen in FIGURE ll which has an outer folded margin 36 and an inner 4folded margin 37. In this instance, the male die element 3S, which depends from the base plate 10 of the upper die, is provided with la centrally disposed annular cavity 39 which, in effect, comprises an inverted female die coacting with thel secondary male die element 4t) projecting upW-ardly from pressure platev 29. The die element 4t) is supported on a movable guide post 41 and biased upwardly by spring 42. The pressure plate 29 mounts a pressure block 43 coacting with the male die element 38; but in this instance the pressure block is cutaway at its center to permit independent movement of the centrally disposed secondary male die element 4t).

FIGURE l2 illustrates the position of the p-arts on the initial down stroke of the upper die assembly, the male die element 38 acting to move the blank 35 downwardly into the fem-ale die cavity 44 formed in die block 15, thereby turning theouter margins 46 of the piece. upwardly. At the same time, the secondary male die element 40 acts to turn the inner marginal edge 37 upwardly against the wall surfaces of the centrally disposed annual cavity 39. As before, the pressure plate 29 will be locked in its lowermost position so thatl the piece .will be retained in the cavity 44 as the rnale die element 38 is withdrawn. Thereafter, upon forward movement of the sliding plate 19, an annular cavity 45 (FIGURE 13) in the under-y surface of the plate 19 will be aligned with the female cavity 44 so that, upon subsequent downward movement of the die-block 15, the upwardly projecting marginal areas 36 and 37 will be concurrently folded inwardly into the annular cavity 45. In this connection, it will be noted that the secondary male die element 40 will be compressed against its spring 42.

While thus far the invention has been described in terms of decorative pieces in which the marginal edges are folded directly on themselves, it is to be understood that the folding operations may be conducted with or without accompanyingl stiifening elements for the pieces being folded. Thus, in FIGURES 14 and l5 there is illustrated a decorative piece Sti in the nature of a disc to the upper surface of which a stiifening element 51 has been adhered, the exposed marginal portions 52 vof With this the underlying piece 50 being adapted to be folded about the stiiening element.

Referring now to FIGURES 16 through 18, there is illustrated an embodiment of the invention for folding the ornamental piece 50 and stripping it from the die element in a single operation. That is, a single stroke of the movable die is all that is required to both fold and strip the piece. In this instance, the sliding plate 19 of the prior embodiment is not required, and the die block 53 is provided in its upper surface with a recess 54 of a size to receive the flat blank. A female die cavity'55 extends downwardly from the recess and is normally closed by a pressure block 56 mounted on a spring biased pressure plate 57.

The cooperating male die element 58 is provided on its under surface with a recessed cavity 59 corresponding in cross-section-al area to the cross-sectional area of the female die cavity; and it is also provided with a secondary recess 60 adapted to receive the plunger 61 which is normally biased to the projecting position illustrated in FIGURE 16 by means of a spring 62. j

In this embodiment of the invention, as the male die element 58 starts its downward Imovement the plunger 61v first contacts the center of the ornamental piece and deiiects it downwardly into the female die cavity, in the manner seen in FIGURE 17, the plunger also serving to depress the pressure block 56 and plate 57. To this end,l

the force of the spring 62 is greater than the force of the springs supporting the pressure block 56 and plate 57. The marginal portions 52 of -the piece are thus folded upwardly about the edges of the stiffener 51. The presence of the stiffener eliminates the need for theplunger 61 to extend outwardly to the marginal portions of'the piece to form a folding edge for the marginal area being folded. The di-mensioning of the parts is such that the under surface of the male die element -58 surrounding the cavity 59 will contact the shoulder of the recess 54, in the manner seen in FIGURE 17, whereupon continued downward movement of the male die element 58 serves to depress the die block 53 relative tothe pressure block 56, thereby causing the parts to assume the position illustrated in FIGURE 18, wherein it will be seen the marginal edges of the piece have been folded about the stiffener. Thereafter, as the upper and lower die elements sep-arate .on the upward movement of the upper platen, the compressed plungerl will -be freed for movement under the influence of a spring 62, thereby effectively stripping the folded piece from the cavity 59 and, upon complete separation of the die elements, the pressure block 56 will return to its uppermost position, thereby pushing the folded piece upwardly for ready removal from the device.

It will be understood, of course, that similar single stroke mechanisms may be employed to form sh-apes other than the circular disc disclosed. For example, the bow' illustrated in FIGURE 9 can be readily formed inl this manner, as could diverse other shapes. Similarly, other modifications may be made in the invention Without departing from the spirit and purpose of it. The particular press employed may be varied as may its mode of operation. Thus, suitable timing means may be provided to provide a dwell, either mechanically or operator controlled as to its duration, during the initial press operation. Similar- 1y, whereas the treadle is operator tripped for the second press stroke employed in the embodiment OFIGURES 4 8, for example, the gearing of the press may be such that there Will be a quick sh-arp stroke with no dwell. Other modifications falling within the ambit of the instant invention will undoubtedly occur to the worker in the art upon reading specification, and consequently it is not intended that the invention be limited excepting in the manner set -forth in the claims which follow. Having thus described the invention in certain exemplary embodiments, what it is desired to secure and protect by Letters Patent is:

l. In apparatus for folding the edges of a decorative workpiece, coacting upper and lower die assemblies, said lower die assembly comprising a base plate mounting a die block, means for resiliently sustaining said die block spaced upwardly from said base plate, a die cavity in said block configured to conform to the con-tour of the folded workpiece, a pressure block movably mounted in said die cavity of substantially the same dimensions as said die cavity, means resiliently sustaining said pressure block in said die cavity with the upper surface of said block essentially coplanar with the upper edge of said `die cavity, means surrounding the upper end .of said die cavity for receiving and positioning an unfoldedy workpiece in alignment therewith, said upper die assembly comprising a base plate mounting a depending folding element of lesser dimensions than said die cavity and movable into said die cavity to press the workpiece downwardly therein against said pressure block with the marginal-edges of the workpiece folded upwardly against the sides of said die cavity; and means defining a shallow folding cavity having inwardly curved edges adapted to be juxtaposed to the upper end of said die cavity with the edges of said folding cavity in alignment with the edges of said die cavity, whereby upon upward movement of said projecting folding element from said die cavity and relative movement between said die block and said pressure block, the upwardly projecting edges of the Workpiece will be pressed into said folding cavity and infolded thereby.

2. The device claimed in claim l wherein the means defining said folding cavity comprises a die block fixedly I.secured to theJ base plate ofy said upper die assembly, wherein said depending folding element comprises a plunger resiliently sustained in said die block, and wherein said last named die block is provided with a 4,secondary recess into which said plunger is adapted to be retracted.

3. The device claimed in claim 2 wherein the means surrounding the upper end of said die cavity for receiving and positioning an unfolded workpiece comprises a shallow recess formed in said first named die block, and wherein said recess defines a shoulder against which the die block forming a part of said upper die assembly is adapted to seat, whereby downward movement 4of said upper die assembly will effect downward movement of said first named die block relative to its base plate and the pressure block mounted thereon.

4. The device claimed in claim l wherein said lower die assembly includes a slidable plate mounted for horizontal movement over the upper surface of said die block, wherein said slidable plate has an orifice therein configured to conform to the contour of said die cavity, and wherein the lmeans surrounding the upper end of said die cavity for receiving and positioning an unfolded workpiece comprises a shallow recess formed in the upper surface of said slidable plate.

5. The device claimed in claim 4 wherein the means defining said folding cavity comprises an extention of said slidable plate, said folding cavity being formed in the under surface of said slidable plate and laterally spaced from the orifice therein, said slidable plate being movable from a position in which said orifice is in vertical alignment with said die cavity to a position wherein said shallow cavity is in alignment with said die cavity.

6. The device claimed in claim 5 wherein said upper die assembly mounts at least one depending stripping pin, and wherein said slidable plate has at least one pin receiving opening therein in alignment with said shallow l cavity, said pin being aligned with said opening when the orifice in said sliding plate is in vertical alignment with said die cavity.

7. The device claimed in claim l wherein said pressure block is mounted on a pressure plate resiliently sustained beneath said die block, and wherein said base plate mounts latch means operative to lock said pressure plate in depressed condition.

lower die assembly comprising a base plate, a die block overlying said base plate in' spaced rel-ation thereto, spring means supportingwsaid die blocksaid die block being depressable' against the compression of said spring means, a die cavity in said die block configured to conform to the contour of the ,folded workpiece, guide means at the upper end of said'dieA cavity for aligning an unfolded Vworkpiecetherewith, a pressure plate underlying the cavity in said die block and mounting a pressure block projecting upwardly linto said cavity, spring means normally urging said pressure plate upwardly to a position in which the upper surface of said pressure block coin- -eides with the upper edgeiof said die cavity, said pressure plate and block beingdepressible against their supporting springs,:latch means mounted on said'base plate operative lto engage and retain said pressure plate in depressed po sition, said latch means having cam surfaces engageable `by said dieblock uponfdepression thereof to release said pressure plate, said upper die assembly comprising a A Vbase plate mounting a depending die element of lesser dimensionsV than said die cavity and adaptedlto enter therein to urge the workpiece against said pressure block.

10. The device claimed in claim 9 wherein said die block has a planar upper surface mounting a horizontally slidable plate, wherein said plate has an orice therein. congured to conform to they contour of said die cavity but of slightly lesser dimensions tlran'said die cavity and yet of a size to freelyreceive said die element, said ori- -flce being surrounded Vby a shallow recess dening a support for the marginal edges of an unfolded workpiece.

11. The device claimed in claim 10 wherein atfolding cavity is formed in the undersurface of ysaid sliding plate in laterally spaced relation to the orifice therein, wherein said folding cavity is congured to conform to the contour of said die cavity and has inwardly rounded edges, and wherein saidv slidable plate is movable from first position in which said orice overlies said die cavity to a second position wherein said folding cavity overlies said die cavity.

12. The device claimed in claim 11 wherein said slidable plate has a plurality of apertures therein opening intosaid shallow folding cavity, and wherein said upperdie assembly includes a plurality of depending stripping pins adapted to pass through said apertures when said orice is in vertical alignment with said die cavity and said upper die assembly is moved downwardly relative to said lower die assembly. v

i3. In apparatus for lfolding the edges of a decorative workpiece, coacting upper and lower die assemblies, said lower die assembly comprisinga base plate, a die block overlyin" said base plateV in spaced relation thereto, spring means supporting said die block, said die block being depress'ible against-*the compression of said spring means, a die cavity insaid die 'block con'iigured to oonforrn to the contour ofthe folded workpiece, a pressure plate underlying thel cavity in said die block and mount- `ing a pressure block Yprojecting upwardly into said cavity, spring means normally urging lsaid pressure plate upwardly to a position in which'the upper surface of said pressure bloc; substantially coincides with the upper edges of saiddie cavity, said pressure plate and block vbeing jointly depressible-a'gainst the springsk supporting said pressure plate, latch means mounted on said base plate operative to engage and retain said pressure plate in depressed position, said latchY means having cam surfaces ycontactable by said die block upon depression thereof to release said pressure plate, said die block having a planar upper surface mounting a horizontally slid- -able plate,'an `orifice in said plate configured to conform to the contour of said die cavity, a shallow recess surrounding the orifice in said slidable plate and defining a support for the marginal edges of an unfolded workpiece, a folding cavity formed in the undersurface of said sliding plate in laterally kspaced relation to the orifice therein, said folding lcavity being configured to conform to the contour of said die cavity and having inwardly rounded edges, said slidable plate being movable from a iirst position in which said orifice yoverlies said die cavity to a second position wherein said folding kcavity overlies said die cavity, said upper die assembly comprising a base plate mounting a depending die element of a size to enter the die cavity of said lower die assembly and urge a workpiece supported on said sliding plate against said pressure block.

'14. The deviceclaimed'in claim 13 wherein the orii'ce in said slidable plate is of slightly lesser dimensions than said die cavity and yet of a size to slidably receive a depending die element forming ya part of said coacting upper die assembly, whereby the edges of said plate sur-l rounding said orice dene an abutment eifective to prevent accidental withdrawal of the workpiece from said ds cavitywhile said slidable plate is in its rst position o use.

15. The device claimed in claim 14 wherein said slidable plate has a plurality of apertures therein opening into said shallow folding cavity, and wherein said upper die assembly includes a plurality of depending stripping pins positioned to pass through said apertures when said oriiice is in vertical alignment with said die cavity and said upper die assembly is moved downwardly relative to said lower die assembly.

No references cited.

fr LIM 

1. IN APPARATUS FOR FOLDING THE EDGES OF A DECORATIVE WORKPIECE, COACTING UPPER AND LOWER DIE ASSEMBLIES, SAID LOWER DIE ASSEMBLY COMPRISING A BASE PLATE MOUNTING A DIE BLOCK, MEANS FOR RESILIENTLY SUSTAINING SAID DIE BLOCK SPACED UPWARDLY FROM SAID BASE PLATE, A DIE CAVITY IN SAID BLOCK CONFIGURED TO CONFORM TO THE CONTOUR OF THE FOLDED WORKPIECE, A PRESSURE BLOCK MOVABLY MOUNTED IN SAID DIE CAVITY OF SUBSTANTIALLY THE SAME DIMENSIONS AS SAID DIE CAVITY, MEANS RESILIENTLY SUSTAINING SAID PRESSURE BLOCK IN SAID DIE CAVITY WITH THE UPPER SURFACE OF SAID BLOCK ESSENTIALLY COPLANAR WITH THE UPPER EDGE OF SAID DIE CAVITY, MEANS SURROUNDING THE UPPER END OF SAID DIE CAVITY FOR RECEIVING AND POSITIONING AN UNFOLDED WORKPIECE IN ALIGNMENT THEREWITH, SAID UPPER DIE ASSEMBLY COMPRISING A BASE PLATE MOUNTING A DEPENDING FOLDING ELEMENT OF LESSER DIMENSIONS THAN SAID DIE CAVITY AND MOVABLE INTO SAID DIE CAVITY TO PRESS THE WORKPIECE DOWNWARDLY THEREIN AGAINST SAID PRESSURE BLOCK WITH THE MARGINAL EDGES OF THE WORKPIECE FOLDED UPWARDLY AGAINST THE SIDES OF SAID DIE CAVITY; AND MEANS DEFINING A SHALLOW FOLDING CAVITY HAVING INWARDLY CURVED EDGES ADAPTED TO BE JUXTAPOSED TO THE UPPER END OF SAID DIE CAVITY WITH THE EDGES OF SAID FOLDING CAVITY IN ALIGNMENT WITH THE EDGES OF SAID DIE CAVITY, WHEREBY UPON UPWARD MOVEMENT OF SAID PROJECTING FOLDING ELEMENT FROM SAID DIE CAVITY AND RELATIVE MOVEMENT BETWEEN SAID DIE BLOCK AND SAID PRESSURE BLOCK, THE UPWARDLY PROJECTING EDGES OF THE WORKPIECE WILL BE PRESSED INTO SAID FOLDING CAVITY AND INFOLDED THEREBY. 